Compound for the treatment of photographic prints.



FTQ

CHARLES B. WAITE, OF MEXICO, MEXICO.

COMPOUND FOR THE TREATMENT OF PHOTOGRAPHIC PRINTS.

To all whom it may concern:

Be it known that I, CHARLES B. WArrn, a

citizen of the United States, residing at city of Mexico. Mexico, haveinvented certain new and useful Improvements in Compounds for theTreatment of Photographic Prints, of which the following is aspecification.

This invention relates to photography, and

particularly to treatment of photographic prints.

The object ofthe invention is to provide a preparation or compound forremoving yellow or brownish stains such as frequently appear uponphotographic prints after the same have been developed. The inventionmay also be used to reduce the color of photographs which have been overprinted, or exposed to the light too long in the printing operation.

Not only may the invention be employed in connection with ordinary photoprints but itis contemplated to use the same in the manner abovedescribed on any photographs obtained by the process of developmentafter short exposure of a negative or positive, and includes bromidenlargements, all papers or prints adapted to be printed by gas light,and also certain printing out papers which have for their base a silveremulsion combined with gelatin or collodion.

My compound consists of the following ingredients in substantially theproportions specified:

Water 10 ounces. Cyanid of potassium 1 ounce. Ammonia (28%) l0 drams.Borax 20 grains.

Carbolic acid In the actual use of my preparation the cyanid ofpotassium affects the underlying emulsion of the photographic print, itsaction being to produce a separation of this emulsion, together with thephotograph carried thereby, from the base on which it is placed. Byusing the ammonia and borax in connection with the cyanid of potassiumthe effect of the latter is neutralized somewhat, the uneven separationof the emulsion 3 drams.

from the base carrying the same, and the production of spots which wouldruin the Specification of Letters Patent.

Application filed August 10, 1908.

Patented Aug. 10, 1909.

Serial No. 447,743.

photograph being thus prevented. By con tinued experiments I have foundthat the use of ammonia and borax in the proportions stated enables meto secure the best results in theactual practice of my invention.

Were the cyanid employed in the present compound without the ammonia andborax, the action of the compound would be uneven, having a tendency tocause white streaks and spots on the print. The ammoniaand borax byretarding the action of the cyanid thus produce uniformity in thereducing or clearing process, and this is to great advantage in thepractical embodiment of the invention, in fact is absolutely essentialto obtain proper results.

The carbolic acid included in my compound is designed to neutralize thepoison- "ous effect of the fumes of the cyanid of potassium, which wouldbe inhaled by the operator and might result in serious injury. The fumesof the cyanid are dissipated by the carbolic acid and renderedpractically harmless in this way. These fumes are also purified to acertain extent.

In treating photographic prints with my preparation I apply saidpreparation to the prints with a tuft of cotton, or the like, afterwhich the prints are again placed in the fixing bath and thoroughlywashed. The discoloring stains will be removed by applying the compoundin the above manner or the same operation will reduce the color ofprints should they have been printed too dark through inadvertence.

Having thus described the invention, what is claimed as new, is:

A compound for treatment of photographic prints including the followingingredients in substantially the proportions specified: water, tenounces; cyanid of potassium, one ounce; ammonia, ten drains; borax,twenty grains; and carbolic acid, three drams.

In testimony whereof I aflix my signature in presence of two witnesses.

CHARLES B. WAITE.

WVitness%:

O. PIQUETTE MrronnLL, G. A. GUERRA.

